This study seeks to identify sociodemographic variations in mental disorder and the use of mental health services among adult blacks. The study will use the non-institutionalized and institutionalized black sample from the National Institute of Mental Health (NIMH) Epidemiologic Catchment Area (ECA) program to empirically examine the variability within the black population. Analyses will systematically assess the extent to which socioeconomic status, gender, age, and marital status are associated with the prevalence and incidence of discrete psychiatric disorders and helpseeking among blacks. All analyses will be replicated for the white sample of the ECA data to distinguish those risk factors that operate similarly from those that operate differently across race. In contrast to most studies of black mental health which use small or geographically limited samples and/or symptom checklists, this study uses a large heterogeneous black sample, and measures of psychiatric disorder based on the Diagnostic Interview Schedule (DIS). The significance of this study must be assessed against the background of the extremely fragmentary evidence that is currently available about the heterogeneity of the black population with regard to factors that influence mental health status and helpseeking behavior.